diff --git a/backend/src/cyclone/api.py b/backend/src/cyclone/api.py
index f339139..ff4ea88 100644
--- a/backend/src/cyclone/api.py
+++ b/backend/src/cyclone/api.py
@@ -941,7 +941,7 @@ async def parse_ta1_endpoint(
             rows = (
                 link_s.query(Batch)
                 .filter(
-                    Batch.kind == "837",
+                    Batch.kind == "837p",
                     Batch.raw_result_json.isnot(None),
                 )
                 .order_by(Batch.parsed_at.desc())
diff --git a/backend/src/cyclone/claim_acks.py b/backend/src/cyclone/claim_acks.py
index d217c71..5be7a77 100644
--- a/backend/src/cyclone/claim_acks.py
+++ b/backend/src/cyclone/claim_acks.py
@@ -141,7 +141,7 @@ def lookup_claims_for_ack_set_response(
         # callers SHOULD pass the index.
         rows = (
             session.query(Batch.id, Batch.raw_result_json)
-            .filter(Batch.kind == "837")
+            .filter(Batch.kind == "837p")
             .all()
         )
         for bid, raw in rows:
diff --git a/backend/src/cyclone/handlers/handle_ta1.py b/backend/src/cyclone/handlers/handle_ta1.py
index 518e4a6..9c1c289 100644
--- a/backend/src/cyclone/handlers/handle_ta1.py
+++ b/backend/src/cyclone/handlers/handle_ta1.py
@@ -75,7 +75,7 @@ def handle(
             rows = (
                 session.query(db.Batch)
                 .filter(
-                    db.Batch.kind == "837",
+                    db.Batch.kind == "837p",
                     db.Batch.raw_result_json.isnot(None),
                 )
                 .order_by(db.Batch.parsed_at.desc())
diff --git a/backend/src/cyclone/store/claim_acks.py b/backend/src/cyclone/store/claim_acks.py
index cedd35e..dbbdc4e 100644
--- a/backend/src/cyclone/store/claim_acks.py
+++ b/backend/src/cyclone/store/claim_acks.py
@@ -78,7 +78,7 @@ def batch_envelope_index() -> dict[str, str]:
     with db.SessionLocal()() as s:
         rows = (
             s.query(Batch.id, Batch.raw_result_json)
-            .filter(Batch.kind == "837")
+            .filter(Batch.kind == "837p")
             .all()
         )
         for bid, raw in rows:
diff --git a/backend/tests/test_api_claim_acks.py b/backend/tests/test_api_claim_acks.py
index 48325f2..3e5ecf8 100644
--- a/backend/tests/test_api_claim_acks.py
+++ b/backend/tests/test_api_claim_acks.py
@@ -56,7 +56,7 @@ def _seed_batch_envelope(*, batch_id: str, envelope_control: str):
     with db.SessionLocal()() as s:
         b = Batch(
             id=batch_id,
-            kind="837",
+            kind="837p",
             input_filename=f"{batch_id}.txt",
             parsed_at=datetime(2026, 7, 2, 12, 0, tzinfo=timezone.utc),
             raw_result_json={
diff --git a/backend/tests/test_apply_claim_ack_links.py b/backend/tests/test_apply_claim_ack_links.py
index 76fab46..3eebace 100644
--- a/backend/tests/test_apply_claim_ack_links.py
+++ b/backend/tests/test_apply_claim_ack_links.py
@@ -78,7 +78,7 @@ def _seed_batch(
     ``batch_envelope_index``."""
     b = Batch(
         id=batch_id,
-        kind="837",
+        kind="837p",
         input_filename=f"{batch_id}.txt",
         parsed_at=datetime(2026, 7, 2, 12, 0, tzinfo=timezone.utc),
         raw_result_json={
@@ -378,7 +378,7 @@ def test_ta1_links_to_most_recent_matching_batch():
         def _batch_lookup(sender_id, receiver_id):
             rows = (
                 s.query(Batch)
-                .filter(Batch.kind == "837")
+                .filter(Batch.kind == "837p")
                 .order_by(Batch.parsed_at.desc())
                 .all()
             )
diff --git a/backend/tests/test_e2e_999_to_claim_drawer.py b/backend/tests/test_e2e_999_to_claim_drawer.py
index dfce842..4dc6ac9 100644
--- a/backend/tests/test_e2e_999_to_claim_drawer.py
+++ b/backend/tests/test_e2e_999_to_claim_drawer.py
@@ -64,7 +64,7 @@ def _seed_batch_envelope(*, batch_id: str, envelope_control: str):
     with db.SessionLocal()() as s:
         b = Batch(
             id=batch_id,
-            kind="837",
+            kind="837p",
             input_filename=f"{batch_id}.txt",
             parsed_at=datetime(2026, 7, 2, 12, 0, tzinfo=timezone.utc),
             raw_result_json={